Mentioning BuildUp is confusing

I think mentioning BuildUp all over the docs is confusing. People who are wondering "what is git-building?" are confronted with a website essentially answering with "let me tell you about BuildUp!". (And then also shows them a graph of documents that tries to capture all the intricacies of linking between them).

I think we should restrict mention of BuildUp to some notes to people who are wondering if they can re-use this syntax somewhere else.